History of the condition  

The definitive cause of OCD is still unknown.

Mystic beliefs
During the 14th and 15th century it was believed that that those who experienced obsessive thoughts were possessed by the devil.
That’s why the treatment involved banishing the evil from the possessed patient through exorcism.

Freud’s theory
In the early 1900s, the famous psychologist Freud attributed obsessive-compulsive behavior to unconscious conflicts which manifested as the symptoms of the disorder. He linked OCD to stressors or traumas that occurred during childhood. However there is still not enough evidence to support this theory.

Possible causes of OCD

There are many different theories about the cause of obsessive-compulsive disorder. Let's take a look at some of the more accepted theories.

Abnormalities of some brain structures

One research study has discovered a type of size abnormality in different brain structures. The experts are claiming that there is some type of abnormality in the neurotransmitter serotonin in the case of Obsessive-Compulsive Disorder. It has been discovered that serotonin has a role to play in regulating anxiety, though it is also thought to be involved in sleep and memory function. In order to function properly serotonin must bind to the receptor sites and that’s why experts believe that OCD sufferers may have blocked or damaged receptor sites. This would then prevent serotonin from functioning to its full potential. It is proven that OCD patients benefit from the use of Selective Serotonin Reuptake Inhibitors - a class of antidepressant medications that increase the levels of serotonin in circulation.

Genetic mutations

Some experts claim that a genetic mutation that could be the cause of OCD. Researchers have indeed found a mutation in the human serotonin transporter gene in unrelated families with OCD. In addition, it has also been proven that environmental factors also play a role in how these anxiety symptoms are expressed; in other words, it is possible that your genetics make you vulnerable to developing Obsessive-Compulsive Disorder, but your environment determines whether you actually will. 

Different brain activities

Using some brain imaging techniques such as positron emission tomography (PET scans), it has been shown that those patients with OCD tend to have brain activity that differs from those who do not have this disorder. That’s why some experts claim that OCD is caused by the part of the brain that is responsible for translating complex intentions into fundamental actions. This part of the brain is failing to correctly communicate with other structures in the brain in these cases, or so the theory goes. 

Infections and hormonal imbalances

Some cases of OCD are thought to be caused at least in part by childhood streptococcal infections. This is because it is found that the streptococcal antibodies may become involved in an autoimmune process. If OCD is caused by bacteria, this provides hope that antibiotics may eventually be utilized to treat or prevent it. Some experts are also saying that OCD in men may be partially caused by low estrogen levels.

Nutrition deficiencies

There are also several studies which have shown that nutrition deficiencies may be a cause for OCD and other mental disorders. That’s why certain vitamin and mineral supplements may help people with such disorders and provide the nutrients necessary for proper mental functioning.